1. Field of the Invention
The present invention relates to a wheel balance weight which is to be attached to a wheel by adhesion (hereinafter, an adhesion-type balance weight) and a method of manufacturing the same.
2. Description of Related Art
In an automobile wheel assembly including a wheel and a tire, there is a potential for a dynamic imbalance in weight to exist when the wheel is rotated. Generally, in order to compensate for this imbalance, the wheel is provided with a balance weight.
Increasingly, an adhesion-type balance weight has been used for the following reasons:
(1) From the standpoint of wheel design, a clip-type balance weight (a balance weight to be attached to a wheel by a clip) which is disposed on the visible design surface of the wheel has been replaced by the adhesion-type balance weight which can be attached to an inside surface of a non-visible portion of the wheel.
(2) It is often difficult to attach the clip-type balance weight to a flange portion of the wheel, because the flange has a specialized configuration.
(3) Due to improvement of wheel and tire technology, the weight of the balance weight is decreased, which enables the use of an adhesion-type balance weight.
A conventional adhesion-type balance weight includes a weight body manufactured by cast and made from Pb (lead) having a bar configuration, and an adhesive double-coated tape to which the weight body is attached. A separating sheet protects the adhesion surface of the tape. The sheet is removed when the balance weight is used.
In order to keep the adhesive strength of the balance weight to the wheel, it is preferable that the surface of the balance weight which is attached to the wheel has the same curvature as that of the inside surface of the wheel. Since Pb has high plasticity, the balance weight can be easily formed, even manually, to match the same curvature as that of the inside surface of the wheel.
Recently, there has been a trend to avoid the industrial use of heavy metals such as Pb for the purpose of an environmental protection. Thus, the Pb of the balance weight is apt to be substituted for other materials.
As an alternative, from an industrial viewpoint materials such as Fe or Cu can be used which are inexpensive, environmentally friendly and have a relatively high density.
In cases where the adhesion-type balance weight is made from the materials such as Fe and Cu, which are harder than Pb, it is difficult to form the balance weight to the same curvature as that of the inside surface of the wheel by manual force.
Further, since the weight of the balance weight is weighed in standard weights which are defined in 5 gram intervals from 5 g to 100 g, many balance weights of 5, 10, 15, . . . , 100 g need to be prepared.
Some conventional adhesion-type balance weights which are made of Pb have slits at each interval of the unit weight. Thus, each slit allows the balance weight to be easily cut according to the required weight. Balance weights made from Pb are softer and are easily cut. Further, no problems with corrosion occur at the cut plane. On the contrary, a balance weight made from steel requires a greater cutting force. In addition, there is a possibility of corrosion generation if a bare surface of a steel balance weight is exposed, which requires a surface re-treatment after cutting.